These latices commonly have an average molecular weight of 100,000 or more. They are stable suspensions whose average latex particle size typically is about 2,000-5,000 .ANG., or even larger. Latex concentration in the waste dealt with here ordinarily is about 1-6% by weight; rarely does it reach as much as 20%. While such latices may at times have a bit of ionic functionality in their molecular structures, they are to be distinguished from the more highly ionizable lyophobic colloid-type coating resins and resinous mixtures made for aqueous dispersion such as those shown in Example 1 of our parent application Ser. No. 346,958. The latter resins typically have average molecular weight below 40,000, and they disperse into water in a much finer particulate condition.
In said parent application we have shown a practical way to form a leach-resistant consolidate of low volume from the thinly-dispersed, comparatively low molecular weight resinous material and from latex wastes that are structurally fairly acidic or, if practically neutral, are deliberately acidulated. The process of said parent application involves using portland cement to flocculate the dispersoid and collecting the resulting small volume cementiferous floc. Such processing is to be distinguished from prior proposals for converting an initial volume of waste water (including one containing dispersed polymer) into a massive concretion with portland cement and aggregate (for example, as shown in U.S. Pat. Nos. 4,116,705 and 4,149,968). Such resulting concretion (for landfill or other disposal) can be larger than the original volume of the aqueous waste submitted to treatment.
Heretofore it has been proposed to flocculate and settle latex for disposal using, for example, flocculants including complex organic ones. Such processes are slow, often expensive, and frequently they produce a waste mass or sludge that can be difficult to handle, In our U.S. Pat. No. 4,132,759 of Jan. 26, 1982, we have shown an efficient way to form a leach-resistant consolidate from aqueous latex paint wastes. The process involves flocculating such waste with an organic flocculating agent, then heating the waste body to a fairly high temperature. The process is reasonably rapid. The sludge consolidates well, and it can be handled with facility.
The instant invention is distinguishable from the process of our U.S. Pat. No. 4,132,759 in that it uses a little cement, rather than the heating of the entire aqueous waste mass, in the process of obtaining the leach-resistant consolidate; the resulting consolidate is a more brittle one (because of the cement addition). Unlike the process of the parent application here, the cement in the instant operation can be used in a much lesser effective proportion, and it is not used as a flocculant, but rather to enhance, surprisingly, the separability of a floc already initiated. The resulting cementiferous sludge is of relatively minor volume in comparison to the volume of the aqueous waste submitted to such treatment. This, of course, is in sharp contrast to concretion processes referred to above which employ cement.